1. Field of the Invention
The present invention relates to an image synthesizing method of synthesizing a plurality of images each including a duplicate image area to form a single synthesized image.
2. Related Background Art
As a method of synthesizing a plurality of images to form an image having a wide angle of view, a method is known by which two images are synthesized by designating matching points in overlapping area of the two images and putting one matching point over the other. With this method, the matching points of the two images are required to be designated by a mouse or the like and this operation is cumbersome.
Extracting matching points may be executed automatically by template matching or the like to detect the positional relationship between two images and synthesize them.
Such conventional techniques, however, are associated with the following problems because a synthesizing process for two images is required to be executed a plurality of times if a panorama image of 360 degrees is to be formed by synthesizing images taken with an ordinary taking lens or if a large image with a high resolution is to be synthesized.
For example, in synthesizing four images, first a synthesized image of first and second images is formed, and then another synthesized image is formed from third and fourth images. The two synthesized images are synthesized to form a final synthesized image of the four images.
In this case, image data is required to be synthesized after the positional relationships between the first and second images, between the third and fourth images, and between the two synthesized images, are detected.
It is not so difficult to synthesize four images if the positional relationships between all images are known in advance. However, since a synthesizing process for two images is performed a plurality of times to synthesize image data, the process efficiency is poor.
If the matching points are automatically extracted by template matching or the like to detect the positional relationship between two images, two images are required to be designated at each of a plurality of synthesizing processes for two images. Therefore, even if the matching points are not required to be manually designated, the operation is cumbersome.
As a method of synthesizing a plurality of images to form an image having a wide angle of view, a method is known by which two images are synthesized by subjecting the two images to geometric conversion such as affine transformation so as to make the two same points in the duplicate areas of the two images coincide with each other.
With this conventional technique, however, it is necessary to recognize the duplicate areas of two images and extract the same two points (hereinafter called matching points) from the duplicate areas. This operation may be performed by displaying two images to be synthesized on a display screen and designating the matching points in the two images with a mouse or the like. With this method, however, the matching points are required to be manually designated so that the operation is not simple and some skill is necessary.
Template matching is a method of automatically extracting the matching points from two images. With this method, one image is divided into small areas and each area is compared with the other image to detect the matching points which are images most analogous to each other.
With this template matching, if the duplicate areas of two images to be synthesized are not designated in advance, erroneous matching points may be extracted in some cases from the areas other than the duplicate areas of the two images. Therefore, an extraction precision of matching points is lowered. With a lowered extraction precision of matching points, two images cannot be synthesized correctly.
Also with this template matching, if a broad duplicate area of one image is designated as a search area of a matching point and this broad duplicate area contains many analogous areas, it takes a long time to extract the matching points from the designated two duplicate areas, and therefore the two images cannot be synthesized quickly.
It is an object of the present invention to provide an image synthesizing method capable of solving the above problems.
It is another object of the present invention to provide an image synthesizing method capable of efficiently synthesizing three or more images with simple operations.
Under the above objects, according to one embodiment of the present invention, an image synthesizing method for synthesizing a plurality of images partially overlapping with each other is provided which comprises the steps of: inputting a plurality of image data each corresponding to a plurality of image, extracting a matching point of duplicate areas of desired two images partially overlapping with each other among a plurality of images represented by the plurality of input image data, and sequentially detecting a position relationship between two images in accordance with the extracted matching point; detecting the position relationships of all images in accordance with the position relationship between two images sequentially detected by the position relationship detecting step; and synthesizing the images represented by the plurality of input image data in accordance with the position relationships of all images detected by the all image position relationship detecting step to form a synthesized image.
It is another object of the present invention to provide an image synthesizing method capable of synthesizing three or more images and forming a synthesized image having a good image quality at a desired image area, with simple operations.
Under the above objects, according to one embodiment of the present invention, an image synthesizing method for synthesizing a plurality of images partially overlapping with each other is provide which comprises the steps of: inputting a plurality of image data each corresponding to a plurality of images and arranging the plurality of images of the plurality of input image data in a display area; extracting a matching point of duplicate areas of desired two images partially overlapping with each other among a plurality of images arranged at the arranging step and sequentially detecting a position relationship between two images in accordance with the extracted matching point; forming a data list of an order of detecting the position relationship, an image associated with the matching point, and a position of the image associated with the matching point in the display area, in accordance with the position relationship between two images in the display area sequentially detected by the position relationship detecting step; detecting the position relationships of all images from the position relationship between two images sequentially detected, in accordance with the data list formed by the data list forming step; and synthesizing the images of the plurality of input image data in accordance with the position relationships of all images detected by the all image position relationship detecting step to form a synthesized image.
It is another object of the present invention to provide an image synthesizing method capable of automatically and precisely synthesizing a plurality of images without complicated operations.
Under the above objects, according to one embodiment of the present invention, an image synthesizing method for synthesizing a plurality of images partially overlapping with each other is provided which comprises the steps of: inputting a plurality of image data each corresponding to a plurality of images, stepwise reducing the plurality of images of the plurality of input image data at different reduction factors and generating a plurality of reduced image data of the reduced images; stepwise extracting a matching point of images of the reduced image data generated by the reduced image data generating step and sequentially from the reduced image data of a reduced image having a largest reduction factor to equal-size image data of an image having the same size as the image represented by the plurality of input image data; setting various parameters necessary for image conversion synthesization in accordance with the matching point extracted by the matching point extracting step; if the various parameters set by the parameter setting step are for a reduced image of the reduced image data at the matching point extracting step, estimating a duplicate area of a plurality of images of the reduced image data having a one-step higher reduction factor by using the matching point extracted by the matching point extracting step and the various parameters set by the parameter setting step, setting as a template of a small area for extracting the matching point in each reduced image among the plurality of reduced images, and extracting at the matching point extracting step the matching point in the plurality of reduced images of the size reduced image data having the one-step higher reduction factor, whereas if the various parameters set by the parameter setting step are for an image of the equal-size image data at the matching point extracting step, converting at least one image among the plurality of images of the plurality of input image data to synthesize with another image.
It is a further object of the present invention to provide an image synthesizing method capable of automatically and precisely synthesizing a plurality of images in a short processing time.
Under the above objects, according to one embodiment of the present invention, an image synthesizing method for synthesizing a plurality of images partially overlapping with each other is provided which comprises the steps of: inputting a plurality of image data each corresponding to a plurality of images, stepwise reducing the plurality of images of the plurality of input image data at different reduction factors, and generating a plurality of reduced image data of the reduced images; extracting a feature image of the reduced image of the reduced image data generating step from the reduced image data generated by the reduced data generating step and generating reduced feature image data; stepwise extracting a matching point of images of feature images of the reduced feature image data generated by the feature image data generating step, sequentially from the reduced feature image data of a reduced image having a largest reduction factor to equal-size feature image data of a feature image having the same size as the image represented by the plurality of input image data; setting various parameters necessary for image conversion synthesization in accordance with the matching point extracted by the matching point extracting step; if the various parameters set by the parameter setting step are for a reduced feature image of the reduced feature image data at the matching point extracting step, estimating a duplicate area of a plurality of reduced images of the reduced image data having a one-step higher reduction factor by using the matching point extracted by the matching point extracting step and the various parameters set by the parameter setting step, setting as a template a small area for extracting the matching point in each reduced feature image among the plurality of reduced feature images, and extracting at the matching point extracting step the matching point in the plurality of reduced feature images of the reduced feature image data having the one-step higher reduction factor, whereas if the various parameters set by the parameter setting step are for an image of the equal-size feature image data at the matching point extracting step, converting at least one image among the plurality of images of the plurality of input image data to synthesize with another image.
The above and other objects of the present invention will become apparent from the following detailed description of embodiments of the invention when read in conjunction with the accompanying drawings.